Chromium complex main group

The reported complexes of chromium(III) with group IV ligands are limited mainly to those containing CN and to a lesser extent those containing other C donor ligands. 

Interaction of metals with cyclopropenylidene to form stable complexes has been widely studied340 in the last two decades since the first reported synthesis of pentacarbonyl(2,3-diphenylcyclopropenylidene)chromium (see belowy4. Two groups of cyclopropenylidene metal derivatives may be distinguished neutral cyclopropenylidene complexes represented by two resonance forms, and the cationic cyclopropenylium transition metal complexes of groups 6 (Cr, Mo, W), 7 (Mn), 8 (Fe) and 10 (Pd, Pt), whereas the latter cationic cr-complexes are derived from both main group metals (Li, Mg) and group 10 (Pd, Pt) transition metals. 

Acid dyes include metal-complexed azo structures, where the metals used are cobalt, chromium, and iron.10 Examples are 1 1 and 2 3 chromium complexes and 1 2 cobalt complexes, where the numbers employed represent the ratio of metal atoms to dye molecules. Metal-complexed dyes can be formed inside textile fibers by treating suitably dyed fibers with a solution containing metal ions.11 In this case, the metal-free forms of these azo dyes are known as mordant dyes and contain mainly ortho, ortho -bis-hydroxy or ortho-carboxy, ortho -hydroxy groups (e.g., C.I. Mordant Black 11, Mordant Yellow 8, and Mordant Orange 6). When the metal complexes are formed prior to the dye application process, the resultant dyes are known as... 

Generally, arene(alkoxy)carbene chromium complexes react with aryl-, alkyl-, terminal or internal alkynes in ethers or acetonitrile to yield 4-alkoxy-l-naphthols, with the more hindered substituent ortho to the hydroxyl group . Upon treatment with alkynes, aryl(dialkylamino)carbene chromium complexes do not yield aminonaphthols, but they form indene derivatives . Vinyl(dialkylamino)carbene complexes, however, react with alkynes to yield aminophenols as the main products The solvent is one of the many factors that affects this type of reaction, for which the most important is the polarity and/or coordinating ability of the solvent. The Dotz benzannulation reaction yields either arene chromium tricarbonyl complexes or the decomplexed phenols, depending on the work-up conditions. Oxidative work-up yields either decomplexed phenols or the corresponding quinones. 

The most commonly used transition metal compounds are those of titanium, vanadium, chromium, and zirconium. The transition metal-carbon bond is formed by the action of an organometallic compound of the main group elements, leading to the formation of the complex which has catalytic properties. 

The iro-propyl and tm-butyl chromium complexes are unusual. Presumably, it is steric bulk that is preventing the P-C—H bond from reaching the metal. These structures seem to be sterically saturated. The examples containing noncoplanar M—C—C—H groups mainly involve cyclic alkyls, in which the rigidity of the ring system holds the M—C—C—H dihedral angle near 60°... 

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